In order to keep a material away from an element located in an essentially closed volume, wherein this element could be damaged by this material, it is known to introduce into the volume an adsorber in the form of a solid or granular material, wherein the adsorber collects the material, and thus keeps it away from the element. For example, electronic components are sensitive to humidity, which condenses out. A hygroscopic insert, which is arranged in the immediate vicinity of the component in a shared housing, withdraws the moisture from the air, whereby the condensing out is prevented. Known adsorbers include, for example, zeolite and silica gel. The collecting ability of an adsorber is, however, limited, so that knowledge concerning the degree of saturation is desirable.
For determining the water content in a bulk good, from DE 19717711 A1, a measuring cell with two electrodes separated from one another via an intermediate space is known. In the case of introduction of the measuring cell into the bulk good, the intermediate space is filled with the bulk good, so that via a subsequent measuring of conductivity, the moisture content of the bulk good can be determined. A disadvantage in the case of this method is that the quality of the measuring depends on how homogeneously the hollow space is filled with the bulk good. This method is not suitable for determining content of a gas.
Known from DD 135241 is a measurement capacitor for determining the moisture content in the interior of a solid. Bores are made in the solid substance, and, when required, the measurement capacitor is inserted into the bores. For the measuring, the electrodes of the measuring capacitor are pressed onto the wall of the bore, supplied with a high-frequency alternating voltage, and the capacitance is measured, and therefrom, the moisture content is determined. A disadvantage of the invention is that the dimensions of the measuring capacitor and the bores must be matched to one another. In the case of solids of smaller dimensions or of special form, measurement is not possible.